Casters provided with elastic means disposed between the wheel support and the wheel to provide for shock and vibration isolation wherein an elastically resilient material such as an elastomer is used are shown in U.S. Pat. Nos. 3,178,758; 3,041,656; and 1,745,992. In U.S. Pat. No. 3,178,758, an elastomer bushing is mounted in the wheel hub and in conjunction with two linkages, provides vertical compliance for shock and vibration isolation. In U.S. Pat. No. 3,041,656, an elastomer bushing is mounted on the upper caster element and is loaded both radially and in torsion by an L-shaped leg to provide vertical compliance for shock and vibration isolation. In U.S. Pat. No. 1,745,992, an elastomeric compression pad is provided for shock and vibration isolation.
The present invention has in common with the aforesaid patents the use of an elastically resilient body for affording isolation of shock and vibration, but differing therefrom by taking advantage of the torsional resistance of the body to displacement rather than its compressive resistance to displacement. The proposed structure provides for replacing a number of parts with a single part, provides for low profile vibration and shock isolation, and affords a saving in space and weight ordinarily taken up by spring coils and the like.